The sisters, both of Stockwell, south London, were remanded in custody until 11 August.

Mr Osman, also known as Hamdi Issac, is in custody in Italy.

Terrorism Act

He is facing an extradition hearing to bring him back to the UK on 17 August.

The sisters, of separate addresses, are accused of "having information that they knew or believed might be of material assistance in securing the apprehension, prosecution or conviction" of Mr Osman in the UK for "an offence involving the commission, preparation or instigation of an act of terrorism".

The charges, under section 38 of the Terrorism Act, add that they "failed to disclose that information as soon as reasonably practicable to a constable" between 21 July and 28 July.

Baby

The sisters, who held hands throughout the hearing, spoke only to confirm their names, addresses and ages.

Yeshiemebet Girma, said in court to be a mother-of-three with a seven-month-old baby, wore a black and silver headscarf, beige top and green floral skirt.

Her sister, who wore a pale blue jumper and dark grey jeans, waved frequently at two women sat in the public gallery.

The only other person so far charged over the London attacks, Ismael Abdurahman, 23, of Kennington, appeared before Bow Street magistrates on Thursday.

He is also accused of failing to disclose information about the suspected Shepherd's Bush bomber.